Case Study: Mendelian Inheritance and Sickle Cell Anemia

Sickle cell anemia is a genetic disease caused by a mutation in the beta-globin gene responsible for producing an important subunit of hemoglobin. People that have 2 copies of the mutation have the disease, and those that have 1 copy do not have the disease but are considered “carriers”. At the molecular level, abnormalities in the hemoglobin protein cause it to clump, which leads the red blood cells (rbcs) that carry hemoglobin to become misshapen. As a result, the rbcs cannot bind oxygen as efficiently and the body is deprived of oxygen (anemia). The abnormally shaped rbcs also slow down blood flow and become clogged in narrow blood vessels, causing pain. There is no cure for sickle cell anemia, and the goal of treatment is to manage symptoms. Robin, a 30-year-old female, is a carrier for sickle cell anemia. She recently married Brent, who is also a carrier for sickle cell anemia. They want to start having kids immediately but cannot afford the invasive and expensive assisted reproductive technologies that would ensure them a baby without sickle cell anemia. If they decide to have children naturally, they will have a 1-in-4 (25%) chance of producing a child with the disease. Robin has close relatives who suffer significantly with sickle cell anemia, and she does not want to bring a child into the world with the same difficult fate. Brent is more optimistic and takes the view that they have a 3-in-4 (75%) chance of producing a child that does NOT have sickle cell anemia. Robin does not want to “play the odds” and would prefer to adopt, while Brent feels strongly about having a biological child.

Who do you agree with?

Robin. Knowingly conceiving a kid with a 25% chance of having sickle cell anemia is irresponsible as a parent and perpetuates the disease. There are a lot of children waiting to be adopted.

Brent. The odds favor conceiving a child that does NOT have the disease. Biological parenthood is an important value of many people and should not be dismissed lightly.